When I was a kid, back in the early 60’s, this movie scared me half to death. I recently saw it again and realized how silly it was, but I can’t come close to describing it as well as this review from Atomic Monsters!
“Just when it seems the crew is powerless to stop this rampaging alien, they discover a large wooden crate filled with hand grenades! What luck to have those on a space mission! . . . So, while hurtling through space, they decide to detonate more than a dozen grenades. That shouldn’t damage a fragile space vessel! Oh, that’s right — this is the 1950s. The rocket is probably made of concrete, I-beams and coated with pink, lead base paint!”
Read the entire review here, it’s great.